Air purifier



March 9, 1954 w E GROSS 2,671,528

AIR PURIFIER Filed Jan. 25, 1944 MAL/4M. eoss Patented Mar. 9, 1954 AIRPURIFIER William E. Gross, Joppa, Md., assignor to the United States ofAmerica as represented by the Secretary of War Application January 25,1944, Serial No. 519,597

2 Claims. (Cl. 183-49) (Granted under Title 35, U. S. Code (1952),

sec. 266) The invention described herein may be manufactured and used byor for the Goverment for governmental purposes without the payment ofany royalty thereon to me.

This invention relates to apparatus for filtering and purifying aircontaining noxious gases, vapors and/or smokes; more particularly, itrelates to a canister used in connection with gas masks and the like.

In order to render contaminated air fit for breathing, it has been thepractice to use a gas mask with a connected canister, whereby allinhaled air must first pass through the canister to be filtered andpurified therein.

Fundamental requirements of air-purifying canisters are: inexpensivemanufacture, limited use of critical materials, light Weight,compactness, and efficiency in air purification.

Although many varieties of air purifiers are known to have beendeveloped, there has been need for improvements with which thisinvention is concerned.

One object of tihs invention is to simplify and improve the constructionof gas mask canisters so that they more satisfactorily meet the ffundamental requirements.

Among more specific objects, this invention provides an air purifierimproved in the following respects: (a) by minimized internal structure,particularly with avoidance of parts attached inside the canister; (b)prevention of channeling by use of a resilient medium that alsofunctions as a smoke filter; and (c) protection of the air purifierfilling from water, moisture, and oil aerosols. These and other objectswill be apparent from the following description and accompanyingdrawing.

In the drawings are shown two modifications of canisters embodyingfeatures of the invention. The same reference characters refer to likeparts.

Figure 1 diagrammatically illustrates a side elevational cross-sectionview of one canister modification.

Figure 2 illustrates an elevational side view of another canistermodification partly in section.

Referring particularly to the drawing, the canister comprises an outergas-tight and waterproof casing or body I which may be made of sheetmetal. The body may be cylindrical or box shaped.

Referring to Figure l, the body I is crimped or double-seamed in tightengagement with cover 2 that is perforated and preferably dishedinwardly. As shown in Figure 2, the inlet cover 2 may be detachablyfitted to the body by screwing, bead and slot engagement, or a frictionfit so that the canister filling may be readily removed and renewed.

At the outlet end in the upper part of the canister, shown in Figure 1,the body is tightly engaged by double seaming to a valve holder support3 having an outwardly formed bead or rim 4 to facilitate secureattachment to a facepiece. Alternatively, as shown in Figure 2, thecanister body may be drawn to a narrowed neck 5 threaded for securinginto an adapter, a corrugated hose, or valve holder on a facepiece.

Valve seat 6 which is securely engaged to the support 3 has air outletports 'l and a central aperture 8 through which is passed a connectingbutton or fastener 9 that holds the check valve disc IB. The check valvedisc Ill made of rubber or any similar iiexible plastic material isnormally seated so that it closes the ports 'l except when air is beinginhaled through the canister.

A perforated retainer II, preferably dished inwardly, is disposed abovethe filling in the canisters and rests against the shoulder at the upperpart of the body. Advantageously, this retainer does not have to berigidly secured or fastened inside the canister. It may have a snug fitor a loose fit so that it more or less fioats on the lling and can bereadily removed or placed back into the canister on assembly or inmaking repairs.

Between the perforated inlet cover at the bot-- tom and the perforatedretainer II are placed in the order, as shown in Figure l, a layer orpad I2 of highly resilient rock-wool; a decontami-l nating layer I3comprising well known chemical agents including charcoal, whichphysically adsorbs, chemical absorbs, or neutralizes noxious gases; anda layer or pad I4 of fairly resilient rock-wool.

A feature of this invention is that a resilient fibrous inorganicmaterial, particularly one like rock-wool, which is not affected bywater, keeps the granular air-purifying material tightly packed, thusserving to eliminate the need of a spring or other means for preventingloosening and channeling.

When the rock-wool is highly resilient, it

usually has a fair smoke filtering action; and when it is moderatelyresilient, it usuallyhas j;

a very good smoke filtering action, although ,it

does not have suficient resiliency to maintain granules of the chemicalfilling in a compact condition during a, rough usage test. '.Iestsshowed that the canister could stand a rough usage test if a pad ofhighly resilient rock-Wool is placed on one side of the chemical llingand one pad of the less resilient rock-wool is placed on the otherside', thustsandwicliing1 the; chemical 5 lling.Thiscombination'resultedin better smoke protection than when both padswere of the highly resilient rock-wool. As a chemical filling in layerI3 there may 'be used activated charcoalf.,.-

impregnated charcoal, such as Whetlerite, soda-- lime, Hopcalite andvarious;othersfsubstancese. alone or in combinationsfornremoving'fgaseousrs contaminants by chemical and/or physical action.For simplicity, these chemical agentsare. l.

herein referred to as absorbents.` The chemical lling may be made up ofone or morez'layers; As illustrated in Figure 2, waterproolter.

paper may be placed on both sides' 'of thechemief cal lling, i. e., forexample, at I5 adjacent the retainer II above the resilient filtermedium I4 20 protected-on '-bothf sides t from `-waterwl On`^the outletside*the'chemical-'llingis protected'-fromsaliva and on the inlet sideitis protected from` entrance of-*raing-'for the entrance of-water on 2Ail* renderednoxious bythe gas or smoke entersA theicanist'er throughthe perforated -lower cover-1` 2, 4'passesthrong-h" the 'highlyresilient' rock-Wool smokelt'er AI 2 :then -through 'the' chemicalfilter-- inga-bsorbent I=3through the resilient-smoke lter- I 4, andupthroughthe outlet or check-valve ports 1 'I into ahose;adapterfor-suitabie facepiece.

The simplified canister requires a minimumuse 1offmachii'iery,` criticalmaterial such=as steel, and-'skilledelabor Afor'fits :production: It ireadily len-cls"1 itself lto f manufacture from lnon-metallic materials,'such`-as"plastics; -and .even-if made frm- *nf1etal,'` a relativelysmall amount of metal is iused. 2 Byf virtueiof :the tough resilient fnature of the filtering meditimfmade'of a' material such "fas-@rock-L'vvool, the'canister--does not require 'the'50 ing-)roughusage, as contrasted withf conventionalcanisters that require a fairlyhard absorbent to-` prevent-ninger'griningduring rough handling. Tli"e"canisterfcanJ befreadily assenfrbledf- 'repaired' c'andr-enewedbyRunskilld'personnel'f ltepadslimay 'beieutfovepsize so thatwhen4 installed "inlathe canisterf the'yf'expand against the sides andprevent contaminated--'air1from-V channeling-aroundithe edges; as`contrastedfyvith conventionakcanisters thatfrequire sealing-'of' 70ltere-materials 'atth'eA edges-inside thev4 canisterini'orderlto:preventchannelingr# Also, by use'of the resilint'lter Ymedium, the' air ofw'is 4evenly distributed over thecross-sectional'areaofthe absorbent"layeru and thus 'dispenses-with the use 75 of bafflesand other internal structure generally required in conventionalcanisters.

Complete engineering tests on canisters constructed in accordance Withthe present invention prove-'the canister to ibe sati'sfactoryiinjeveryWay. The -chemical filling-was placedain the canisters between theresilient iilter medium pads without having to use expensive vibratingpresses or similar devices for strongly compacting the chemicalabsorbent in order to prevent deformation. andrchannel-irig-,duringrough usage. The rockewoolwltergwasefound to be unaffected by exposureftooilbvapor. or smoke. Canisters were actually submerged in Water for asubstantial period without subsequent damage. When subjectsztoroughusage, no appreciable effect was made on their performance.

With-the" simplified design, the canisters may 13e-adapted for use withcivilian masks, training masks, various service masks and withindustrial masks?` or other-f protective'.v respiratory devices L inlargef-quantitiesfat low costs.:

It is tobe-understood .-thatzthe invention is not.` limited to detailsof construction, herein shown :l 5 byway zofdllustration;smcefvariationsgxvill,readily .occuri-.to those skilled: in the .artiwithoutvdeparting rommheiispirit: of thezinvention; or `err- V ceeding1the :scopef :thezzappended: claims.

I claim:

1. A gas :maskvcanist'erz cylinder: thatwincludes in combination :i apair of f oversize :diameter lter pads paokedzinto'said `canister.cylinder :and held in lateral compression therebyesaidnpads being';composed of mineralfWoolacharacterizedV by its resilience; -adecontaminatingflayer:held in comT pression between f said: pads-.1.solely by, ,vsaidr re silience; -1 and' l'iwiterprooflter=r1neansarranged to arrest the entrancerof moisturefat eachr end of:said kcanisters/1l 2. .Aniaxial-low air, purifier comprising acontainer-f a :iillerefa perforated' fixed ,inlet-plate; i a perforatedoating outlet plate; a valve; meana.

maintaining-said valveJ-inisealed communication withf. said .-outletplate;;.-rwaterpr oof' xlter means at each. end tofsaidscontainerarrangedy -to farrestl the entrance of moisturef-intosaidii1ler;--said,4

llerfconsistngzoffa Ipair Ofrmineral-wool lter pads.-icharacterizedf'by.their resilience :and held.

underlateral ncompression-fin said .container ;r and alayer-ofdecontaminating material held between said pads:inicompressionIexertedl Asolely by said resilience. r

WILLIAM" E. GROSS.

References. Cited inthe lel'of this patentf UNITED STATES PATENTS Numberr Name -Y Date 1,395,833? Kliri'get'al. Nov. 1, 1921 1,499,864r Gordon-July 1, 1924 1,743,675 Jordahl Jan.'14, 1930 1,789,262?? Monroret-ahJan. 13, 1931 1,8663659 Litle, Jri'; July- 12, 1932 1,889,015 Davis Nov;l29,1932 1,963L8T74f-1 Stampe-s. June 19, 1934 2,225g990 F1 Henry s Dec.24, 1940 2,273,779 Dickey et al. Feb. 17, 1942 2,283,0,430'1 Busch May1'2, 1942 2,302,809? Shoeldt'; Nov;V 24, 1942 2,400,7191-x StackhouseMay 21, 1946A FOREIGNFPATENTS f' Number= Country v Date 365,478GreatBritain Jan'..2l, 1932, 510,985 Great Britain Aug. 11, 1939

